pi2 wont boot with larger clusters
larger clusters give better read performance
mkdosfs -s 32 /dev/mmcblk0p1

[root@system76:~]# cat /sys/kernel/debug/mmc0/ios
view the SD bus state on linux


https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=284261
pi4 ddr50 stuff


https://www.raspberrypi.org/forums/viewtopic.php?t=241182
https://www.raspberrypi.org/forums/viewtopic.php?p=1777011
https://goughlui.com/static/multicid.htm
https://goughlui.com/2014/01/02/project-read-collect-decode-sd-card-cid-register-data/
CID decoding